Name

shorewall.conf — Shorewall global configuration file

Synopsis

/etc/shorewall/shorewall.conf

Description

This file sets options that apply to Shorewall as a whole.

The file consists of Shell comments (lines beginning with '#'), blank lines and assignment statements
(variable=value). If the
value contains shell meta characters or white-space,
then it must be enclosed in quotes. Example:
MACLIST_LOG_LEVEL="NFLOG(1,0,1)".

OPTIONS

Many options have as their value a log-level.
Log levels are a method of describing to syslog (8) the importance of a
message and a number of parameters in this file have log levels as their
value.

These levels are defined by syslog and are used to determine the
destination of the messages through entries in /etc/syslog.conf (5). The
syslog documentation refers to these as "priorities"; Netfilter calls them
"levels" and Shorewall also uses that term.

Valid levels are:

7 debug
6 info
5 notice
4 warning
3 err
2 crit
1 alert
0 emerg

For most Shorewall logging, a level of 6 (info) is appropriate.
Shorewall log messages are generated by NetFilter and are logged using
facility 'kern' and the level that you specify. If you are unsure of the
level to choose, 6 (info) is a safe bet. You may specify levels by name or
by number.

If you have built your kernel with ULOG and/or NFLOG target support,
you may also specify a log level of ULOG and/or NFLOG (must be all caps).
Rather than log its messages to syslogd, Shorewall will direct netfilter
to log the messages via the ULOG or NFLOG target which will send them to a
process called 'ulogd'. ulogd is available with most Linux distributions
(although it probably isn't installed by default). Ulogd is also available
from http://www.netfilter.org/projects/ulogd/index.html
and can be configured to log all Shorewall messages to their own log
file.

Note

If you want to specify parameters to ULOG or NFLOG (e.g.,
NFLOG(1,0,1)), then you must quote the setting.

Example:

MACLIST_LOG_LEVEL="NFLOG(1,0,1)"

Beginning with Shorewall 5.0.0, the log level may be followed by a
colon (":") and a log tag. The log tag normally
follows the packet disposition in Shorewall-generated Netfilter log
messages, separated from the disposition by a colon (e.g, "DROP:mytag").
See LOGTAGONLY below for additional information.

Beginning with Shorewall 4.4.22, LOGMARK is also a valid level which
logs the packet's mark value along with the other usual information. The
syntax is:

LOGMARK[(priority)]

where priority is one of the levels
listed in the list above. If omitted, the default is info (6).

The following options may be set in shorewall.conf.

ACCEPT_DEFAULT={action[(parameters)][:level]|none}

DROP_DEFAULT={action[(parameters)][:level]|none}

NFQUEUE_DEFAULT={action[(parameters)][:level]|none}

QUEUE_DEFAULT={action[(parameters)][:level]|none}

REJECT_DEFAULT={action[(parameters)][:level]|none}

In earlier Shorewall versions, a "default action" for DROP and
REJECT policies was specified in the file
/usr/share/shorewall/actions.std.

In Shorewall 4.4.0, the DROP_DEFAULT, REJECT_DEFAULT,
ACCEPT_DEFAULT, QUEUE_DEFAULT and NFQUEUE_DEFAULT options were
added.

DROP_DEFAULT describes the rules to be applied before a
connection request is dropped by a DROP policy; REJECT_DEFAULT
describes the rules to be applied if a connection request is
rejected by a REJECT policy. The other three are similar for ACCEPT,
QUEUE and NFQUEUE policies.

The value applied to these may be:

The default values are:

DROP_DEFAULT="Drop"

REJECT_DEFAULT="Reject"

ACCEPT_DEFAULT="none"

QUEUE_DEFAULT="none"

NFQUEUE_DEFAULT="None"

If you set the value of either option to "None" then no
default action will be used and the default action or macro must be
specified in shorewall-policy(5).

You can pass parameters to the
specified action (e.g.,
myaction(audit,DROP)).

Beginning with Shorewall 4.5.10, the action name can be
followed optionally by a colon and a log
level. The level will be applied to each
rule in the action or body that does not already have a log
level.

ACCOUNTING=[Yes|No]

Added in Shorewall 4.4.7. If set to Yes, Shorewall accounting
is enabled (see shorewall-accounting(5)).
If not specified or set to the empty value, ACCOUNTING=Yes is
assumed.

ACCOUNTING_TABLE=[filter|mangle]

Added in Shorewall 4.4.20. This setting determines which
Netfilter table the accounting rules are added in. By default,
ACCOUNTING_TABLE=filter is assumed. See also shorewall-accounting(5).

ADD_IP_ALIASES=[Yes|No]

This parameter determines whether Shorewall automatically adds
the external address(es) in shorewall-nat(5). If the
variable is set to Yes or yes then Shorewall automatically adds these
aliases. If it is set to No or
no, you must add these aliases
yourself using your distribution's network configuration
tools.

If this variable is not set or is given an empty value
(ADD_IP_ALIASES="") then ADD_IP_ALIASES=Yes is assumed.

Warning

Addresses added by ADD_IP_ALIASES=Yes are deleted and
re-added during shorewall reload
and shorewall restart. As a
consequence, connections using those addresses may be
severed.

ADD_SNAT_ALIASES=[Yes|No]

This parameter determines whether Shorewall automatically adds
the SNAT ADDRESS in shorewall-masq(5). If
the variable is set to Yes or
yes then Shorewall automatically
adds these addresses. If it is set to No or no,
you must add these addresses yourself using your distribution's
network configuration tools.

If this variable is not set or is given an empty value
(ADD_SNAT_ALIASES="") then ADD_SNAT_ALIASES=No is assumed.

Warning

Addresses added by ADD_SNAT_ALIASES=Yes are deleted and
re-added during shorewall reload
and shorewall restart. As a
consequence, connections using those addresses may be
severed.

When ADMINISABSENTMINDED=No, only traffic to/from those
addresses listed in routestopped is
accepted when Shorewall is stopped. When
ADMINISABSENTMINDED=Yes, in addition to traffic to/from
addresses in routestopped, connections
that were active when Shorewall stopped continue to work and
all new connections from the firewall system itself are
allowed.

Note that the routestopped file is not supported in
Shorewall 5.0 and later versions.

stoppedrules

All existing connections continue to work. To sever all
existing connections when the firewall is stopped, install the
conntrack utility and place the command conntrack
-F in the stopped user exit
(/etc/shorewall/stopped).

If ADMINISABSENTMINDED=No, only new connections matching
entries in stoppedrules are accepted when
Shorewall is stopped. Response packets and related connections
are automatically accepted.

If ADMINISABSENTMINDED=Yes, in addition to connections
matching entries in stoppedrules, all new
connections from the firewall system itself are allowed when
the firewall is stopped. Response packets and related
connections are automatically accepted.

If this variable is not set or is given the empty value then
ADMINISABSENTMINDED=No is assumed.

ARPTABLES=[pathname]

Added in Shorewall 4.5.12. This parameter names the arptables
executable to be used by Shorewall. If not specified or if specified
as a null value, then the arptables executable located using the
PATH option is used.

Regardless of how the arptables utility is located (specified
via arptables= or located via PATH), Shorewall uses the
arptables-restore and arptables-save utilities from that same
directory.

AUTOCOMMENT=[Yes|No]

Formerly named AUTO_COMMENT. If set, if there is not a current
comment when a macro is invoked, the behavior is as if the first
line of the macro file was "COMMENT <macro name>". The
AUTO_COMMENT option has a default value of 'Yes'.

AUTOHELPERS=[Yes|No]

Added in Shorewall 4.5.7. When set to Yes
(the default), the generated ruleset will automatically associate
helpers with applications that require them (FTP, IRC, etc.). When
configuring your firewall on systems running kernel 3.5 or later, it
is recommended that you:

Set AUTOHELPERS=No.

Modify the HELPERS setting (see below) to list the helpers
that you need.

Specify the appropriate helper in the HELPER column in
shorewall-rules
(5).

Note

The macros for those applications requiring a helper
automatically specify the appropriate HELPER where
required.

AUTOMAKE=[Yes|No]

If set, the behavior of the start,
reload and
restart commands are changed; if no files in
CONFIG_PATH (see below) have been changed since the last successful
start, reload or restart
command, then the compilation step is skipped and the compiled
script that executed the last start, reload or restart command
is used. The default is AUTOMAKE=No.

The setting of the AUTOMAKE option is ignored if the
start, reload or
restart command includes a directory name
(e.g., shorewall restart
/etc/shorewall.new).

BASIC_FILTERS=[Yes|No]

Added in Shorewall-4.6.0. When set to Yes, causes entries in shorewall-tcfilters(5) to
generate a basic filter rather than a u32 filter. This setting
requires the Basic Ematch capability in your
kernel and iptables.

Note

One of the advantages of basic filters is that ipset matches
are supported in newer iproute2 and kernel versions. Because
Shorewall cannot reliably detect this capability, use of basic
filters is controlled by this option.

The default value is No which
causes u32 filters to be generated.

BLACKLIST=[{ALL|state[,...]}]

where state is one of NEW, ESTABLISHED, RELATED, INVALID,or
UNTRACKED.

Added in Shorewall 4.5.13 to replace the BLACKLISTNEWONLY
option. Specifies the connection tracking states that are to be
subject to blacklist screening. If BLACKLIST is not specified then
the states subject to blacklisting are
NEW,ESTABLISHED,INVALID,UNTRACKED.

ALL sends all packets through the blacklist chains.

Note: The ESTABLISHED state may not be specified if
FASTACCEPT=Yes is specified.

BLACKLIST_DISPOSITION=[DROP|A_DROP|REJECT|A_REJECT]

This parameter determines the disposition of packets from
blacklisted hosts. It may have the value DROP if the packets are to
be dropped or REJECT if the packets are to be replied with an ICMP
port unreachable reply or a TCP RST (tcp only). If you do not assign
a value or if you assign an empty value then DROP is assumed.

A_DROP and A_REJECT are audited versions of DROP and REJECT
respectively and were added in Shorewall 4.4.20. They require
AUDIT_TARGET in the kernel and iptables.

The BLACKLIST_DISPOSITION setting has no effect on entries in
the BLACKLIST section of shorewall-rules (5). It
determines the disposition of packets sent to the blacklog target of shorewall-blrules
(5).

BLACKLIST_LOG_LEVEL=[log-level[:log-tag]]

Formerly named BLACKLIST_LOGLEVEL. This parameter determines
if packets from blacklisted hosts are logged and it determines the
syslog level that they are to be logged at. Its value is a syslog
level (Example: BLACKLIST_LOG_LEVEL=debug). If you do not assign a
value or if you assign an empty value then packets from blacklisted
hosts are not logged. The setting determines the log level of
packets sent to the blacklog target
of shorewall-blrules(5).

CHAIN_SCRIPTS={Yes|No}

Added in Shorewall 4.5.16. Prior to the availability of BEGIN
PERL....END PERL in configuration files, the only way to execute a
chain-specific script was to create a script file with the same name
as the chain and place it in a directory on the CONFIG_PATH. That
facility has the drawback that the compiler will attempt to run a
non-script file just because it has the same name as a chain. To
disable this facility, set CHAIN_SCRIPTS=No. If not specified or
specified as the empty value, CHAIN_SCRIPTS=Yes is assumed.

CLAMPMSS=[Yes|No|value]

This parameter enables the TCP Clamp MSS to PMTU feature of
Netfilter and is usually required when your internet connection is
through PPPoE or PPTP. If set to Yes or yes,
the feature is enabled. If left blank or set to No or no,
the feature is not enabled.

You may also set CLAMPMSS to a numeric
value (e.g., CLAMPMSS=1400). This will set the
MSS field in TCP SYN packets going through the firewall to the
value that you specify.

CLEAR_TC=[Yes|No]

If this option is set to No
then Shorewall won't clear the current traffic control rules during
[re]start or
reload. This setting is intended for use by
people who prefer to configure traffic shaping when the network
interfaces come up rather than when the firewall is started. If that
is what you want to do, set TC_ENABLED=Yes and CLEAR_TC=No and do
not supply an /etc/shorewall/tcstart file. That way, your traffic
shaping rules can still use the “fwmark” classifier based on packet
marking defined in shorewall-tcrules(5).
If not specified, CLEAR_TC=Yes is assumed.

COMPLETE=[Yes|No]

Added in Shorewall 4.4.12. When you set this option to Yes,
you are asserting that the configuration is complete so that your
set of zones encompasses any hosts that can send or receive traffic
to/from/through the firewall. This causes Shorewall to omit the
rules that catch packets in which the source or destination IP
address is outside of any of your zones. Default is No. It is
recommended that this option only be set to Yes if:

You have defined an interface whose effective physical
setting is '+'.

That interface is assigned to a zone.

You have no CONTINUE policies or rules.

CONFIG_PATH=[directory[:directory]...]

Specifies where configuration files other than shorewall.conf
may be found. CONFIG_PATH is specifies as a list of directory names
separated by colons (":"). When looking for a configuration
file:

If the command is "try" or a "<configuration
directory>" was specified in the command (e.g.,
shorewall check ./gateway) then the directory
given in the command is searched first.

Next, each directory in the CONFIG_PATH setting is
searched in sequence.

If CONFIG_PATH is not given or if it is set to the empty value
then the contents of /usr/share/shorewall/configpath are used. As
released from shorewall.net, that file sets the CONFIG_PATH to
/etc/shorewall:/usr/share/shorewall but your particular distribution
may set it differently. See the output of shorewall show config for
the default on your system.

DEFER_DNS_RESOLUTION=[Yes|No]

Added in Shorewall 4.5.12. When set to 'Yes' (the default),
DNS names are validated in the compiler and then passed on to the
generated script where they are resolved by iptables-restore. This
is an advantage if you use AUTOMAKE=Yes and the IP address
associated with the DNS name is subject to change. When
DEFER_DNS_RESOLUTION=No, DNS names are converted into IP addresses
by the compiler. This has the advantage that when AUTOMAKE=Yes, the
start, reload
and restart commands will succeed even if no DNS
server is reachable (assuming that the configuration hasn't changed
since the compiled script was last generated).

DELETE_THEN_ADD={Yes|No}

If set to Yes (the default value), entries in the
/etc/shorewall/rtrules files cause an 'ip rule del' command to be
generated in addition to an 'ip rule add' command. Setting this
option to No, causes the 'ip rule del' command to be omitted.

DETECT_DNAT_IPADDRS=[Yes|No]

If set to Yes or yes, Shorewall will detect the first IP
address of the interface to the source zone and will include this
address in DNAT rules as the original destination IP address. If set
to No or no, Shorewall will not detect this address
and any destination IP address will match the DNAT rule. If not
specified or empty, “DETECT_DNAT_IPADDRS=Yes” is assumed.

DISABLE_IPV6=[Yes|No]

If set to Yes or yes, IPv6 traffic to, from and through the
firewall system is disabled. If set to No or no,
Shorewall will take no action with respect to allowing or
disallowing IPv6 traffic. If not specified or empty,
“DISABLE_IPV6=No” is assumed.

It is important to note that changing DISABLE_IPV6=Yes to
DISABLE_IPV6=No does not enable IPV6. The
recommended approach for enabling IPv6 on your system is:

Added in Shorewall 5.0.6. When set to Yes,
the generated script will save Docker-generated rules before and
restore them after executing the start,
stop, reload and
restart commands. If set to No
(the default), the generated script will delete any Docker-generated
rules when executing those commands. See
http://www.shorewall.net/Docker.html for additional
information.

Added in Shorewall 4.4.7. When set to No or no,
chain-based dynamic blacklisting using shorewall
drop, shorewall reject,
shorewall logdrop and shorewall
logreject is disabled. Default is Yes. Beginning with Shorewall 5.0.8,
ipset-based dynamic blacklisting using the shorewall
blacklist command is also supported. The name of the set
(setname) and the level
(log_level), if any, at which blacklisted
traffic is to be logged may also be specified. The default set name
is SW_DBL4 and the default log level is none (no
logging). If ipset-only is given, then chain-based
dynamic blacklisting is disabled just as if DYNAMIC_BLACKLISTING=No
had been specified.

Possible options are:

src-dst

Normally, only packets whose source address matches an
entry in the ipset are dropped. If src-dst is
included, then packets whose destination address matches an
entry in the ipset are also dropped.

disconnect

The disconnect option was added in
Shorewall 5.0.13 and requires that the conntrack utility be
installed on the firewall system. When an address is
blacklisted using the blacklist command,
all connections originating from that address are
disconnected. if the src-dst option was also
specified, then all connections to that address are also
disconnected.

timeout=seconds

Added in Shorewall 5.0.13. Normally, Shorewall creates
the dynamic blacklisting ipset with timeout 0 which means that
entries are permanent. If you want entries in the set that are
not accessed for a period of time to be deleted from the set,
you may specify that period using this option. Note that the
blacklist command can override the ipset's
timeout setting.

Important

Once the dynamic blacklisting ipset has been created,
changing this option setting requires a complete restart of
the firewall; shorewall restart if
RESTART=restart, otherwise shorewall stop
&& shorewall start

When ipset-based dynamic blacklisting is enabled, the contents
of the blacklist will be preserved over
stop/reboot/start
sequences if SAVE_IPSETS=Yes, SAVE_IPSETS=ipv4 or if
setname is included in the list of sets
to be saved in SAVE_IPSETS.

EXPAND_POLICIES={Yes|No}

Normally, when the SOURCE or DEST columns in
shorewall-policy(5) contains 'all', a single policy chain is created
and thes policy is enforced in that chain. For example, if the
policy entry is

#SOURCE DEST POLICY LOG
# LEVEL
net all DROP info

then the chain name is 'net-all'
('net2all if ZONE2ZONE=2) which is also the chain named in Shorewall
log messages generated as a result of the policy. If
EXPAND_POLICIES=Yes, then Shorewall will create a separate chain for
each pair of zones covered by the policy. This makes the resulting
log messages easier to interpret since the chain in the messages
will have a name of the form 'a2b' where 'a' is the SOURCE zone and
'b' is the DEST zone.

EXPORTMODULES=[Yes|No]

Added in Shorewall 4.4.17. When set to Yes when compiling for
use by Shorewall Lite (shorewall load,
shorewall reload or shorewall
export commands), the compiler will copy the modules or
helpers file from the administrative system into the script. When
set to No or not specified, the compiler will not copy the modules
or helpers file from /usr/share/shorewall but
will copy those found in another location on the CONFIG_PATH.

When compiling for direct use by Shorewall, causes the
contents of the local module or helpers file to be copied into the
compiled script. When set to No or not set, the compiled script
reads the file itself.

FASTACCEPT={Yes|No}

Normally, Shorewall defers accepting ESTABLISHED/RELATED
packets until these packets reach the chain in which the original
connection was accepted. So for packets going from the 'loc' zone to
the 'net' zone, ESTABLISHED/RELATED packets are ACCEPTED in the
'loc-net' or 'loc2net' chain, depending on the setting of ZONE2ZONE
(see below).

If you set FASTACCEPT=Yes, then ESTABLISHED/RELATED packets
are accepted early in the INPUT, FORWARD and OUTPUT chains. If you
set FASTACCEPT=Yes then you may not include rules in the ESTABLISHED
or RELATED sections of shorewall-rules(5).

FIREWALL=[dnsname-or-ip-address]

This option was added in Shorewall 5.0.13 and may be used on
an administrative system in directories containing the
configurations of remote firewalls. The contents of the variable are
the default value for the system
parameter to the remote-start,
remote-reload and
remote-restart commands.

FORWARD_CLEAR_MARK={Yes|No}

Added in Shorewall 4.4.11. Traditionally, Shorewall has
cleared the packet mark in the first rule in the mangle FORWARD
chain. This behavior is maintained with the default setting of this
option (FORWARD_CLEAR_MARK=Yes). If FORWARD_CLEAR_MARK is set to
'No', packet marks set in the mangle PREROUTING chain are retained
in the FORWARD chains.

GEOIPDIR=[pathname]

Added in Shorewall 4.5.4. Specifies the pathname of the
directory containing the GeoIP Match
database. See http://www.shorewall.net/ISO-3661.html.
If not specified, the default value is
/usr/share/xt_geoip/LE which is the default
location of the little-endian database.

HELPERS=[helper[,helper...]]

Added in Shorewall 4.5.7. This option specifies a
comma-separated list naming the Netfilter application helpers that
are to be enabled. If not specified, the default is to enable all
helpers.

Possible values for helper
are:

amanda

ftp

h323

irc

netbios-ns

none - This special value
was added in Shorewall 4.5.16 and indicates that no helpers are
to be enabled. It also prevents the compiler for probing for
helper support; such probing generates messages on the system
log of the form "xt_CT: No such helper XXX" where XXX is the
helper name. When used, none
must be the only helper specified.

pptp

sane

sip

snmp

tftp

When HELPERS is specified on a system running Kernel 3.5.0 or
later, automatic association of helpers to connections is
disabled.

IGNOREUNKNOWNVARIABLES=[Yes|No]

Added in Shorewall 4.5.11. Normally, if an unknown shell
variable is encountered in a configuration file (except in ?IF and
?ELSIF directives), the compiler raises a fatal error. If
IGNOREUNKNOWNVARIABLES is set to Yes, then such variables simply expand to an
empty string. Default is No.

IMPLICIT_CONTINUE={Yes|No}

When this option is set to Yes, it causes subzones to be treated
differently with respect to policies.

Subzones are defined by following their name with ":" and a
list of parent zones (in shorewall-zones(5)).
Normally, you want to have a set of special rules for the subzone
and if a connection doesn't match any of those subzone-specific
rules then you want the parent zone rules and policies to be
applied; see shorewall-nesting(5).
With IMPLICIT_CONTINUE=Yes, that happens automatically.

If IMPLICIT_CONTINUE=No or if IMPLICIT_CONTINUE is not set,
then subzones are not subject to this special treatment. With
IMPLICIT_CONTINUE=Yes, an implicit CONTINUE policy may be overridden
by including an explicit policy (one that does not specify "all" in
either the SOURCE or the DEST columns).

INLINE_MATCHES={Yes|No}

Added in Shorewall 4.6.0. Traditionally in shorewall-rules(5), a
semicolon separates column-oriented specifications on the left from
alternative
specificaitons on the right.. When INLINE_MATCHES=Yes is
specified, the specifications on the right are interpreted as if
INLINE had been specified in the ACTION column. This also applies to
shorewall-masq(5) and
shorewall-mangle(5) which
also support INLINE. If not specified or if specified as the empty
value, the value 'No' is assumed for backward compatibility.

Beginning with Shorewall 5.0.0, it is no longer necessary to
set INLINE_MATCHES=Yes in order to be able to specify your own
iptables text in a rule and INLINE_MATCHES=Yes is deprecated.
Beginning with 5.0.0, you may simply preface your text with a pair
of semicolons (";;"). If alternate input is also specified in the
rule, it should appear before the semicolons and may be separated
from normal column input by a single semicolon or enclosed in curly
braces ("{....}").

INVALID_DISPOSITION=[A_DROP|A_REJECT|DROP|REJECT|CONTINUE]

Added in Shorewall 4.5.13. Shorewall has traditionally passed
INVALID packets through the NEW section of shorewall-rules (5).
When a packet in INVALID state fails to match any rule in the
INVALID section, the packet is disposed of based on this setting.
The default value is CONTINUE for compatibility with earlier
versions.

INVALID_LOG_LEVEL=log-level[:log-tag]

Added in Shorewall 4.5.13. Packets in the INVALID state that
do not match any rule in the INVALID section of shorewall-rules (5) are
logged at this level. The default value is empty which means no
logging is performed.

IP=[pathname]

If specified, gives the pathname of the 'ip' executable. If
not specified, 'ip' is assumed and the utility will be located using
the current PATH setting.

If this variable is not set or is given an empty value
(IP_FORWARD="") then IP_FORWARD=On is assumed.

IPSET=[pathname]

If specified, gives the pathname of the 'ipset' executable. If
not specified, 'ipset' is assumed and the utility will be located
using the current PATH setting.

IPSET_WARNINGS={Yes|No}

Added in Shorewall 4.5.2. Default is Yes. When set, causes the
rules compiler to issue a warning when:

The compiler is being run by root and an ipset specified
in the configuration does not exists. Only one warning is issued
for each missing ipset.

When [src] is specified in a destination column and when
[dst] is specified in a source column.

IPTABLES=[pathname]

This parameter names the iptables executable to be used by
Shorewall. If not specified or if specified as a null value, then
the iptables executable located using the PATH option is
used.

Regardless of how the iptables utility is located (specified
via IPTABLES= or located via PATH), Shorewall uses the
iptables-restore and iptables-save utilities from that same
directory.

KEEP_RT_TABLES={Yes|No}

When set to Yes, this option prevents
generated scripts from altering the /etc/iproute2/rt_tables database
when there are entries in
/etc/shorewall/providers. If you set this
option to Yes while Shorewall (Shorewall-lite) is
running, you should remove the file
/var/lib/shorewall/rt_tables
(/var/lib/shorewall-lite/rt_tables) before your
next stop, refresh,
restore, reload
or restart command.

The default is KEEP_RT_TABLES=No.

LOAD_HELPERS_ONLY={Yes|No}

Added in Shorewall 4.4.7. When set to Yes, restricts the set
of modules loaded by shorewall to those listed in
/var/lib/shorewall/helpers and those that are actually used. When
not set, or set to the empty value, LOAD_HELPERS_ONLY=No is
assumed.

LOCKFILE=[pathname]

Specifies the name of the Shorewall lock file, used to prevent
simultaneous state-changing commands. If not specified,
${VARDIR}/shorewall/lock is assumed (${VARDIR} is normally /var/lib
but can be changed when Shorewall-core is installed -- see the
output of shorewall show vardir).

LOG_BACKEND=[backend]

Added in Shorewall 4.6.4. LOG_BACKEND determines the logging
backend to be used for the iptrace command (see
shorewall(8)).

backend is one of:

LOG

Use standard kernel logging.

ULOG

Use ULOG logging to ulogd.

netlink

Use netlink logging to ulogd version 2 or later.

LOG_MARTIANS=[Yes|No|Keep]

If set to Yes or yes, sets
/proc/sys/net/ipv4/conf/*/log_martians to 1
with the exception of
/proc/sys/net/ipv4/conf/all/log_martians which is set to
0. The default value is Yes which sets both of the above to one. If
you do not enable martian logging for all interfaces, you may still
enable it for individual interfaces using the logmartians interface option in shorewall-interfaces(5).

The value Keep causes
Shorewall to ignore the option. If the option is set to Yes, then martians are logged on all
interfaces. If the option is set to No, then martian logging is disabled on all
interfaces except those specified in shorewall-interfaces(5).

LOG_VERBOSITY=[number]

This option controls the amount of information logged to the
file specified in the STARTUP_LOG option.

Values are:

-1 - Logging is disabled

0 - Silent. Only error messages are logged.

1 - Major progress messages logged.

2 - All progress messages logged

If not specified, then -1 is assumed.

LOGALLNEW=[log-level]

This option is intended for use as a debugging aid. When set
to a log level, this option causes Shorewall to generate a logging
rule as the first rule in each builtin chain.

The table name is used as the chain name in the log
prefix.

The chain name is used as the target in the log
prefix.

For example, using the default LOGFORMAT, the log prefix for
logging from the nat table's PREROUTING chain is:

Shorewall:nat:PREROUTING

Important

To help insure that all packets in the NEW state are
logged, rate limiting (LOGLIMIT) should be disabled when using
LOGALLNEW. Use LOGALLNEW at your own risk; it may cause high CPU
and disk utilization and you may not be able to control your
firewall after you enable this option.

Caution

Do not use this option if the resulting log messages will
be sent to another system.

LOGFILE=[pathname|systemd]

This parameter tells the /sbin/shorewall program where to look
for Shorewall messages when processing the dump, logwatch, show
log, and hits commands.
If not assigned or if assigned an empty value, /var/log/messages is
assumed. For further information, see http://www.shorewall.net/shorewall_logging.html.
Beginning with Shorewall 5.0.10.1, you may specify
systemd to use journelctl -r to
read the log.

LOGFORMAT=["formattemplate"]

The value of this variable generate the --log-prefix setting
for Shorewall logging rules. It contains a “printf” formatting
template which accepts three arguments (the chain name, logging rule
number (optional) and the disposition). To use LOGFORMAT with
fireparse, set it as:

LOGFORMAT="fp=%s:%d a=%s "

If the LOGFORMAT value contains the substring “%d” then the
logging rule number is calculated and formatted in that position; if
that substring is not included then the rule number is not included.
If not supplied or supplied as empty (LOGFORMAT="") then
“Shorewall:%s:%s:” is assumed.

Note

The setting of LOGFORMAT has an effect of the permitted
length of zone names. See shorewall-zones
(5).

LOGLIMIT=[[{s|d}:]rate/{sec|second|min|minute|hour|day}[:burst]]

Added in Shorewall 4.4.12. Limits the logging rate, either
overall, or by source or destination IP address.

If the value starts with 's:' then logging is limited per
source IP. If the value starts with 'd:', then logging is limited
per destination IP. Otherwise, the overall logging rate is
limited.

If burst is not specified, then a
value of 5 is assumed.

The keywords second and
minute are accepted beginning with
Shorewall 4.6.13.

LOGTAGONLY=[Yes|No]

Using the default LOGFORMAT, chain names may not exceed 11
characters or truncation of the log prefix may occur. Longer chain
names may be used with log tags if you set LOGTAGONLY=Yes. With
LOGTAGONLY=Yes, if a log tag is specified then the tag is included
in the log prefix in place of the chain name.

Beginning with Shorewall 4.5.12, when LOGTAGONLY=Yes, you have
more control over the generated log prefix. Beginning with that
release, the tag is interpreted as a chain
name and a disposition
separated by a comma. So this rule:

#ACTION SOURCE DEST
LOG:info:foo,bar net fw

would generate the following log prefix when using the default
LOGFORMAT setting:

Shorewall:foo:bar:

Similarly,

#ACTION SOURCE DEST
LOG:info:,bar net fw

would generate

Shorewall:net2fw:bar:

MACLIST_DISPOSITION=[ACCEPT|DROP|REJECT|A_DROP|A_REJECT]

Determines the disposition of connections requests that fail
MAC Verification and must have the value ACCEPT (accept the
connection request anyway), REJECT (reject the connection request)
or DROP (ignore the connection request). If not set or if set to the
empty value (e.g., MACLIST_DISPOSITION="") then
MACLIST_DISPOSITION=REJECT is assumed.

A_DROP and A_REJECT are audited versions of DROP and REJECT
respectively and were added in Shorewall 4.4.20. They require
AUDIT_TARGET in the kernel and iptables.

MACLIST_LOG_LEVEL=[log-level[:log-tag]]

Determines the syslog level for logging connection requests
that fail MAC Verification. The value must be a valid syslogd log
level. If you don't want to log these connection requests, set to
the empty value (e.g., MACLIST_LOG_LEVEL="").

MACLIST_TABLE=[filter|mangle]

Normally, MAC verification occurs in the filter table (INPUT
and FORWARD) chains. When forwarding a packet from an interface with
MAC verification to a bridge interface, that doesn't work.

This problem can be worked around by setting
MACLIST_TABLE=mangle which will cause Mac verification to occur out
of the PREROUTING chain. Because REJECT isn't available in that
environment, you may not specify MACLIST_DISPOSITION=REJECT or
MACLIST_DISPOSITION=A_REJECT with MACLIST_TABLE=mangle.

MACLIST_TTL=[number]

The performance of configurations with a large numbers of
entries in shorewall-maclist(5)
can be improved by setting the MACLIST_TTL variable in shorewall.conf(5).

If your iptables and kernel support the "Recent Match" (see
the output of "shorewall check" near the top), you can cache the
results of a 'maclist' file lookup and thus reduce the overhead
associated with MAC Verification.

When a new connection arrives from a 'maclist' interface, the
packet passes through then list of entries for that interface in
shorewall-maclist(5).
If there is a match then the source IP address is added to the
'Recent' set for that interface. Subsequent connection attempts from
that IP address occurring within $MACLIST_TTL seconds will be
accepted without having to scan all of the entries. After
$MACLIST_TTL from the first accepted connection request from an IP
address, the next connection request from that IP address will be
checked against the entire list.

If MACLIST_TTL is not specified or is specified as empty (e.g,
MACLIST_TTL="" or is specified as zero then 'maclist' lookups will
not be cached).

MANGLE_ENABLED=[Yes|No]

Determines whether Shorewall will generate rules in the
Netfilter mangle table. Setting MANGLE_ENABLED=No disables all
Shorewall features that require the mangle table. The default is
MANGLE_ENABLED=Yes.

MAPOLDACTIONS=[Yes|No]

This option is included for compatibility with old Shorewall
configuration. New installs should always have
MAPOLDACTIONS=No.

MINIUPNPD=[Yes|No]

Added in Shorewall 5.0.8. If set to Yes, Shorewall will create
a chain in the nat table named MINIUPNPD-POSTROUTING and will add
jumps from POSTROUTING to that chain for each interface with the
upnpd option specified. Default is No.

MARK_IN_FORWARD_CHAIN=[Yes|No]

If your kernel has a FORWARD chain in the mangle table, you
may set MARK_IN_FORWARD_CHAIN=Yes to cause the marking specified in
the tcrules file to occur in that chain rather than in the
PREROUTING chain. This permits you to mark inbound traffic based on
its destination address when DNAT is in use. To determine if your
kernel has a FORWARD chain in the mangle table, use the shorewall show mangle command; if a FORWARD
chain is displayed then your kernel will support this option. If
this option is not specified or if it is given the empty value
(e.g., MARK_IN_FORWARD_CHAIN="") then MARK_IN_FORWARD_CHAIN=No is
assumed.

MASK_BITS=[number]

Added in Shorewall 4.4.26. Number of bits on the right of the
32-bit packet mark to be masked when clearing the traffic shaping
mark. Must be >= TC_BITS and <= PROVIDER_OFFSET (if
PROVIDER_OFFSET > 0). Prior to Shorewall 5.0.0, default value and
the default values of the other mark layout options is determined as
follows:

Table 1. Default Packet Mark Layout

WIDE_TC_MARKS=No, HIGH_ROUTE_MARKS=No

TC_BITS=8, PROVIDER_BITS=8, PROVIDER_OFFSET=0,
MASK_BITS=8

WIDE_TC_MARKS=No, HIGH_ROUTE_MARKS=Yes

TC_BITS=8, PROVIDER_BITS=8, PROVIDER_OFFSET=8,
MASK_BITS=8

WIDE_TC_MARKS=Yes, HIGH_ROUTE_MARKS=No

TC_BITS=14, PROVIDER_BITS=8, PROVIDER_OFFSET=0,
MASK_BITS=16

WIDE_TC_MARKS=Yes, HIGH_ROUTE_MARKS=Yes

TC_BITS=14, PROVIDER_BITS=8, PROVIDER_OFFSET=16,
MASK_BITS=16

From 5.0.0 onward, the default value of MASK_BITS is 8, the
default value of PROVIDER_BITS, TC_BITS, MASK_BITS and
PROVIDER_OFFSET is 8.

This parameter specifies the directory/directories where your
kernel netfilter modules may be found. If you leave the variable
empty, Shorewall will supply the value
"/lib/modules/$uname/kernel/net/ipv${g_family}/netfilter:/lib/modules/$uname/kernel/net/netfilter:/lib/modules/$uname/kernel/net/sched:/lib/modules/$uname/extra:/lib/modules/$uname/extra/ipset"
where uname holds the output of
'uname -r' and g_family holds '4'.

The option plus sign ('+') was added in Shorewall 5.0.3 and
causes the listed pathnames to be appended to the default list
above.

MULTICAST=[Yes|No]

This option will normally be set to 'No' (the default). It
should be set to 'Yes' under the following circumstances:

You have an interface that has parallel zones defined via
/etc/shorewall/hosts.

You want to forward multicast packets to two or more of
those parallel zones.

In such cases, you will configure a destonly
network on each zone receiving multicasts.

MUTEX_TIMEOUT=[seconds]

The value of this variable determines the number of seconds
that programs will wait for exclusive access to the Shorewall lock
file. After the number of seconds corresponding to the value of this
variable, programs will assume that the last program to hold the
lock died without releasing the lock.

If not set or set to the empty value, a value of 60 (60
seconds) is assumed.

An appropriate value for this parameter would be twice the
length of time that it takes your firewall system to process a
shorewall restart command.

NFACCT=[pathname]

Added in Shorewall 4.5.7. Specifies the pathname of the nfacct
utility. If not specified, Shorewall will use the PATH setting to
find the program.

NULL_ROUTE_RFC1918=[Yes|No|blackhole|unreachable|prohibit]

When set to Yes, causes Shorewall to null-route the IPv4
address ranges reserved by RFC1918. The default value is
'No'.

When combined with route filtering (ROUTE_FILTER=Yes or
routefilter in shorewall-interfaces(5)),
this option ensures that packets with an RFC1918 source address are
only accepted from interfaces having known routes to networks using
such addresses.

The specified value enables certain
optimizations. Each optimization category is associated with a power
of two. To enable multiple optimization categories, simply add their
corresponding numbers together.

Beginning with Shorewall 4.5.20, you may specify OPTIMIZE=All
to enable all optimization categories, and you may also specify
OPTIMIZE=None to disable optimization.

The 1 bit setting also controls the suppression of
redundant wildcard rules (those specifying "all" in the SOURCE
or DEST column). A wildcard rule is considered to be redundant
when it has the same ACTION and Log Level as the applicable
policy.

Note

Optimization level 1 is ignored when optimization level
4 is also selected, since level 4 performs similar
optimizations in a more robust way.

Optimization category 2 - Added in Shorewall 4.4.7. When
set, suppresses superfluous ACCEPT rules in a policy chain that
implements an ACCEPT policy. Any ACCEPT rules that immediately
precede the final blanket ACCEPT rule in the chain are now
omitted.

Optimization category 4 - Added in Shorewall 4.4.7. When
set, causes short chains (those with less than 2 rules) to be
optimized away. The following chains are excluded from
optimization:

accounting chains (unless
OPTIMIZE_ACCOUNTING=Yes)

action chains (user-defined)

'blacklst' chain

dynamic

forwardUPnP

UPnP (nat table)

Additionally:

If a built-in chain has a single rule that branches to
a second chain, then the rules from the second chain are
moved to the built-in chain and the target chain is
omitted.

Chains with no references are deleted.

Accounting chains are subject to optimization if the
OPTIMIZE_ACCOUNTING option is set to 'Yes'.

If a chain ends with an unconditional branch to a
second chain (other than to 'reject'), then the branch is
deleted from the first chain and the rules from the second
chain are appended to it.

An additional optimization was added in Shorewall 4.5.4.
If the last rule in a chain is an unqualified jump to a simple
target, then all immediately preceding rules with the same
simple target are omitted.

Since all of the rules are jumps to the simple target
ACCEPT, this chain is totally optimized away and jumps to the
chain are replace with jumps to ACCEPT.

Optimization category 8 - Added in Shorewall 4.4.9. When
set, causes chains with identical rules to be collapsed into a
single chain.

Optimization category 16 - Added in Shorewall 4.4.26. When
set, causes sequences of compatible rules
to be combined into a single rule. Rules are considered
compatible if they differ only in their destination ports and
comments.

A sequence of compatible rules is often generated when
macros are invoked in sequence.

The ability to combine adjacent rules is limited by two
factors:

Destination port lists may only be combined up to a
maximum of 15 ports, where a port-pair counts as two
ports.

Rules may only be combined until the length of their
concatenated comment reaches 255 characters.

When either of these limits would be exceeded, the current
combined rule is emitted and the compiler attempts to combine
rules beginning with the one that would have exceeded the limit.
Adjacent combined comments are separated by ', '. Empty comments
at the front of a group of combined comments are replaced by
'Others and'. Empty comments at the end of a group of combined
comments are replaced by 'and others'.

Rules with comments "FOO", <empty> and "BAR"
would result in the combined comment "FOO and others,
BAR".

Example 2:

Rules with comments <empty>, "FOO" and "BAR"
would result in the combined comment "Others and FOO,
BAR". Note: Optimize level 16 requires "Extended
Multi-port Match" in your iptables and kernel.

The default value is zero which disables all
optimizations.

OPTIMIZE_ACCOUNTING=[Yes|No]

Added in Shorewall 4.4.7. If set to Yes, Shorewall accounting
changes are subject to optimization (OPTIMIZE=4,5,6 or 7). If not
specified or set to the empty value, OPTIMIZE_ACCOUNTING=No is
assumed.

PAGER=pathname

Added in Shorewall 5.0.6. Specifies a path name of a pager
program like less or more.
When PAGER is given, the output of verbose status
commands and the dump command are piped through
the named program when the output file is a terminal.

Beginning with Shorewall 5.0.12, the default value of this
option is the DEFAULT_PAGER setting in shorewallrc.

PATH=pathname[:pathname]...

Determines the order in which Shorewall searches directories
for executable files.

PERL=pathname

Added in Shorewall 4.4.11 RC1. Specifies the path name of the
Perl executable. Default is /usr/bin/perl. If
the pathname specified by this option does not exist or the named
file is not executable, then Shorewall falls back to
/usr/bin/perl

PROVIDER_BITS=[number]

Added in Shorewall 4.4.26. The number of bits in the 32-bit
packet mark to be used for provider numbers. May be zero. See MASK_BITS above for default value.

PROVIDER_OFFSET=[number]If

Added in Shorewall 4.4.26. The offset from the right
(low-order end) of the provider number field in the 32-bit packet
mark. If non-zero, must be >= TC_BITS (Shorewall automatically
adjusts PROVIDER_OFFSET's value). PROVIDER_OFFSET + PROVIDER_BITS +
ZONE_BITS must be < 32. See MASK_BITS above for default value.

RCP_COMMAND="command"

RSH_COMMAND="command"

Earlier generations of Shorewall Lite required that remote
root login via ssh be enabled in order to use the
load and reload commands.
Beginning with release 3.9.5, you may define an alternative means
for accessing the remote firewall system. In that release, two new
options were added to shorewall.conf:

RSH_COMMAND

RCP_COMMAND

The default values for these are as
follows:

RSH_COMMAND: ssh ${root}@${system} ${command}

RCP_COMMAND: scp ${files}
${root}@${system}:${destination}

Shell variables that will be set when the commands
are invoked are as follows:

root - root user. Normally
root but may be overridden using the '-r'
option.

system - The name/IP address
of the remote firewall system.

command - For RSH_COMMAND,
the command to be executed on the firewall system.

files - For RCP_COMMAND, a
space-separated list of files to be copied to the remote
firewall system.

destination - The directory
on the remote system that the files are to be copied
into.

Added in Shorewall 4.4.27. Shorewall has traditionally
ACCEPTed RELATED packets that don't match any rule in the RELATED
section of shorewall-rules (5).
Concern about the safety of this practice resulted in the addition
of this option. When a packet in RELATED state fails to match any
rule in the RELATED section, the packet is disposed of based on this
setting. The default value is ACCEPT for compatibility with earlier
versions.

RELATED_LOG_LEVEL=log-level[:log-tag]

Added in Shorewall 4.4.27. Packets in the related state that
do not match any rule in the RELATED section of shorewall-rules (5) are
logged at this level. The default value is empty which means no
logging is performed.

REJECT_ACTION=action

Added in Shorewall 4.5.21. When a REJECT target is specified,
Shorewall normally handles the response as follows:

If the destination address of the packet is a broadcast or
multicast address, the packet is dropped.

if the protocol is ICMP (2) then the packet is
dropped.

if the protocol is TCP (6) then the packet is rejected
with an RST.

if the protocol is UDP (17) then the packet is rejected
with an 'port-unreachable' ICMP (ICMP6).

if the protocol is ICMP (1) then the packet is rejected
with a 'host-unreachable' ICMP.

otherwise, the packet is rejected with a 'host-prohibited'
ICMP.

You can modify this behavior by implementing your own
action that handles REJECT and specifying
it's name in this option. The nolog
and inline options will
automatically be assumed for the specified
action.

Added in Shorewall 4.4.10. The default is No. If set to Yes,
at least one optional interface must be up in order for the firewall
to be in the started state. Intended to be used with the Shorewall Init
Package.

RESTART=[restart|reload]

Added in Shorewall 5.0.1 to replace LEGACY_RESTART which was
added in Shorewall 5.0.0. In that release, the reload command was redefined to do what
restart had done in earlier
releases and restart became a true
restart (equivalent to stop
followed by start). When
RESTART=reload, the restart command
performs the same operation as the reload command making it compatible with
earlier releases. If not specified, RESTART=reload is
assumed.

RESTORE_DEFAULT_ROUTE=[Yes|No]

This option determines whether to restore the default route
saved when here are 'balance' providers defined but all of them are
down.

The default is RESTORE_DEFAULT_ROUTE=Yes which preserves the
pre-4.2.6 behavior.

RESTORE_DEFAULT_ROUTE=No is appropriate when you don't want a
default route in the main table (USE_DEFAULT_RT=No) or in the
default table (USE_DEFAULT_RT=Yes) when there are no balance
providers available. In that case, RESTORE_DEFAULT_ROUTE=No will
cause any default route in the relevant table to be deleted.

RESTORE_ROUTEMARKS=[Yes|No]

Added in Shorewall 4.5.9. When set to Yes (the default), provider marks are
restored unconditionally at the top of the mangle OUTPUT and
PREROUTING chains, even if the saved mark is zero. When this option
is set to No, the mark is restored
only if it is non-zero. If you have problems with IPSEC ESP packets
not being routed correctly on output, try setting this option to
No.

RESTOREFILE=filename

Specifies the simple name of a file in /var/lib/shorewall to
be used as the default restore script in the shorewall save, shorewall restore, shorewall forget and shorewall -f start commands.

RETAIN_ALIASES={Yes|No}

During shorewall start, IP
addresses to be added as a consequence of ADD_IP_ALIASES=Yes and
ADD_SNAT_ALIASES=Yes are quietly deleted when shorewall-nat(5) and
shorewall-masq(5)
are processed then are re-added later. This is done to help ensure
that the addresses can be added with the specified labels but can
have the undesirable side effect of causing routes to be quietly
deleted. When RETAIN_ALIASES is set to Yes, existing addresses will
not be deleted. Regardless of the setting of RETAIN_ALIASES,
addresses added during shorewall
start are still deleted at a subsequent shorewall stop, shorewall reload or shorewall restart.

ROUTE_FILTER=[Yes|No|Keep]

If this parameter is given the value Yes or yes
then route filtering (anti-spoofing) is enabled on all network
interfaces which are brought up while Shorewall is in the started
state. The default value is no.

The value Keep causes
Shorewall to ignore the option. If the option is set to Yes, then route filtering occurs on all
interfaces. If the option is set to No, then route filtering is disabled on all
interfaces except those specified in shorewall-interfaces(5).

Important

If you need to disable route filtering on any interface,
then you must set ROUTE_FILTER=No then set routefilter=1 or
routefilter=2 on those interfaces where you want route filtering.
See shorewall-interfaces(5)
for additional details.

RPFILTER_DISPOSITION=[DROP|REJECT|A_DROP|A_REJECT]

Added in Shorewall 4.5.7. Determines the disposition of
packets entering from interfaces the rpfilter
option (see shorewall-interfaces(5)).
Packets disposed of by this option are those whose response packets
would not be sent through the same interface receiving the
packet.

RPFILTER_LOG_LEVEL=log-level[:log-tag]

Added in shorewall 4.5.7. Determines the logging of packets
disposed via the RPFILTER_DISPOSITION. The default value is
info.

SAVE_ARPTABLES={Yes|No}

Added in Shorewall 4.5.12. If SAVE_ARPTABLES=Yes, then the
current arptables contents will be saved by shorewall save command and restored by
shorewall restore command. Default
value is No.

SAVE_IPSETS={Yes|No|ipv4|setlist}

Re-enabled in Shorewall 4.4.6. If SAVE_IPSETS=Yes, then the
current contents of your ipsets will be saved by the shorewall stop and shorewall save commands and restored by the
shorewall start and shorewall restore commands.

Beginning with Shorewall 4.6.4, you can restrict the set of
ipsets saved by specifying a setlist (a comma-separated list of ipv4
ipset names). You may also restrict the saved sets to just the ipv4
ones by specifying ipv4.

SFILTER_DISPOSITION=[DROP|REJECT|A_DROP|A_REJECT]

Added in Shorewall 4.4.20. Determines the disposition of
packets matching the sfilter option (see shorewall-interfaces(5))
and of hairpin packets on interfaces without
the routeback option.[1] interfaces without the routeback option.

SFILTER_LOG_LEVEL=log-level[:log-tag]

Added on Shorewall 4.4.20. Determines the logging of packets
matching the sfilter option (see shorewall-interfaces(5))
and of hairpin packets on interfaces without
the routeback option.[2] interfaces without the routeback option. The default
is info. If you don't wish for these packets to be
logged, use SFILTER_LOG_LEVEL=none.

SHOREWALL_SHELL=[pathname]

This option is used to specify the shell program to be used to
interpret the compiled script. If not specified or specified as a
null value, /bin/sh is assumed. Using a light-weight shell such as
ash or dash can significantly improve performance.

SMURF_DISPOSITION=[DROP|A_DROP]

Added in Shorewall 4.4.20. The default setting is DROP which
causes smurf packets (see the nosmurfs option in shorewall-interfaces(5))
to be dropped. A_DROP causes the packets to be audited prior to
being dropped and requires AUDIT_TARGET support in the kernel and
iptables.

SMURF_LOG_LEVEL=[log-level[:log-tag]]

Specifies the logging level for smurf packets (see the
nosmurfs option in shorewall-interfaces(5)).
If set to the empty value ( SMURF_LOG_LEVEL="" ) then smurfs are not
logged.

STARTUP_ENABLED={Yes|No}

Determines if Shorewall is allowed to start. As released from
shorewall.net, this option is set to No. When set to Yes or yes,
Shorewall may be started. Used as a guard against Shorewall being
accidentally started before it has been configured.

STARTUP_LOG=[pathname]

If specified, determines where Shorewall will log the details
of each start, reload, restart, refresh, try, and safe-* command. Logging verbosity is
determined by the setting of LOG_VERBOSITY above.

SUBSYSLOCK=[pathname]

This parameter should be set to the name of a file that the
firewall should create if it starts successfully and remove when it
stops. Creating and removing this file allows Shorewall to work with
your distribution's initscripts. For RedHat and OpenSuSE, this
should be set to /var/lock/subsys/shorewall. For Debian, the value
is /var/lock/shorewall and in LEAF it is /var/run/shorewall.

TC=[pathname]

If specified, gives the pathname of the 'tc' executable. If
not specified, 'tc' is assumed and the utility will be located using
the current PATH setting.

TC_BITS=[number]

The number of bits at the low end of the 32-bit packet mark to
be used for traffic shaping marking. May be zero. See MASK_BITS above for default value.

TC_ENABLED=[Yes|No|Internal|Simple|Shared]

If you say Yes or yes here, Shorewall will use a script that
you supply to configure traffic shaping. The script must be named
'tcstart' and must be placed in a directory on your
CONFIG_PATH.

If you set TC_ENABLED=Internal or internal or leave the option
empty then Shorewall will use its builtin traffic shaper
(tc4shorewall written by Arne Bernin.

Beginning with Shorewall 4.4.15, you can set
TC_ENABLED=Shared. This allows you to configure the tcdevices and
tcclasses in your Shorewall6 configuration yet make them available
to the compiler when compiling your Shorewall configuration. In
addition to setting TC_ENABLED=Shared, you need to create symbolic
links from your Shorewall configuration directory (normally
/etc/shorewall/) to the tcdevices and tcclasses files in your
Shorewall6 configuration directory (normally
/etc/shorewall6/).

TC_EXPERT={Yes|No}

Normally, Shorewall tries to protect users from themselves by
preventing PREROUTING and OUTPUT tcrules from being applied to
packets that have been marked by the 'track' option in shorewall-providers(5).

If you know what you are doing, you can set TC_EXPERT=Yes and
Shorewall will not include these cautionary checks.

TC_PRIOMAP=map

Added in Shorewall 4.4.6. Determines the mapping of a packet's
TOS field to priority bands. See shorewall-tcpri(5). The
map consists of 16 space-separated digits with
values 1, 2 or 3. A value of 1 corresponds to Linux priority 0, 2 to
Linux priority 1, and 3 to Linux Priority 2. The first entry gives
the priority of TOS value 0, the second of TOS value 1, and so on.
See tc-prio(8) for additional information.

The default setting is TC_PRIOMAP="2 3 3 3 2 3 1 1 2 2 2 2 2 2
2 2".

TCP_FLAGS_DISPOSITION=[ACCEPT|DROP|REJECT|A_DROP|A_REJECT]

Determines the disposition of TCP packets that fail the checks
enabled by the tcpflags interface
option (see shorewall-interfaces(5))
and must have a value of ACCEPT (accept the packet), REJECT (send an
RST response) or DROP (ignore the packet). If not set or if set to
the empty value (e.g., TCP_FLAGS_DISPOSITION="") then
TCP_FLAGS_DISPOSITION=DROP is assumed.

A_DROP and A_REJECT are audited versions of DROP and REJECT
respectively and were added in Shorewall 4.4.20. They require
AUDIT_TARGET in the kernel and iptables.

TCP_FLAGS_LOG_LEVEL=[log-level[:log-tag]]

Determines the syslog level for logging packets that fail the
checks enabled by the tcpflags interface option. The value must be a
valid syslogd log level. If you don't want to log these packets, set
to the empty value (e.g., TCP_FLAGS_LOG_LEVEL="").

TRACK_PROVIDERS={Yes|No}

Added in Shorewall 4.4.3. When set to Yes, causes the
track option to be assumed on all providers defined
in shorewall-providers(5).
May be overridden on an individual provider through use of the
notrack option. The default value is 'No'.

Beginning in Shorewall 4.4.6, setting this option to 'Yes'
also simplifies PREROUTING rules in shorewall-tcrules(5).
Previously, when TC_EXPERT=No, packets arriving through 'tracked'
provider interfaces were unconditionally passed to the PREROUTING
tcrules. This was done so that tcrules could reset the packet mark
to zero, thus allowing the packet to be routed using the 'main'
routing table. Using the main table allowed dynamic routes (such as
those added for VPNs) to be effective. The rtrules file was created
to provide a better alternative to clearing the packet mark. As a
consequence, passing these packets to PREROUTING complicates things
without providing any real benefit. Beginning with Shorewall 4.4.6,
when TRACK_PROVIDERS=Yes and TC_EXPERT=No, packets arriving through
'tracked' interfaces will not be passed to the PREROUTING rules.
Since TRACK_PROVIDERS was just introduced in 4.4.3, this change
should be transparent to most, if not all, users.

TRACK_RULES={Yes|No|File}

Added in Shorewall 4.5.20. If set to Yes, causes the compiler to add a comment to
iptables rules to indicate the file name and line number of the
configuration entry that generated the rule. If set to No (the default), then no such comments are
added.

Setting this option to Yes
requires the Comments capability in iptables
and kernel.

Beginning with Shorewall 5.0.5, the option may also be set to
File. That setting causes similar
comments to be added to the
.iptables-restore-input file, which is normally
created in /var/lib/shorewall.

Added in Shorewall 4.5.13. Shorewall has traditionally passed
UNTRACKED packets through the NEW section of shorewall-rules (5).
When a packet in UNTRACKED state fails to match any rule in the
UNTRACKED section, the packet is disposed of based on this setting.
The default value is CONTINUE for compatibility with earlier
versions.

UNTRACKED_LOG_LEVEL=log-level[:log-tag]

Added in Shorewall 4.5.13. Packets in the UNTRACKED state that
do not match any rule in the UNTRACKED section of shorewall-rules (5) are
logged at this level. The default value is empty which means no
logging is performed.

USE_DEFAULT_RT=[Yes|No]

When set to 'Yes', this option causes the Shorewall multi-ISP
feature to create a set of routing rules which are resilient to
changes in the main routing table. Such changes can occur for a
number of reasons, VPNs going up and down being an example. The idea
is to send packets through the main table prior to applying any of
the Shorewall-generated routing rules. So changes to the main table
will affect the routing of packets by default.

When USE_DEFAULT_RT=Yes:

Both the DUPLICATE and the COPY columns in providers(5)
file must remain empty (or contain "-").

The default route is added to the the 'default' table
rather than to the main table.

balance is assumed unless
loose is specified.

Packets are sent through the main routing table by a rule
with priority 999. In routing_rules(5),
the range 1-998 may be used for inserting rules that bypass the
main table.

All provider gateways must be specified explicitly in the
GATEWAY column. detect may not
be specified.

Note

detect may be
specified for interfaces whose configuration is managed by
dhcpcd. Shorewall will use dhcpcd's database to find the
interface's gateway.

You should disable all default route management outside of
Shorewall. If a default route is added to the main table while
Shorewall is started, then all policy routing will stop working
(except for those routing rules in the priority range
1-998).

Prior to Shorewall 4.6.0, if USE_DEFAULT_RT was not set or if
it was set to the empty string then USE_DEFAULT_RT=No was assumed.
Beginning with Shorewall 4.6.0, the default is USE_DEFAULT_RT=Yes
and use of USE_DEFAULT_RT=No is deprecated.

Warning

The enable, disable
and reenable commands do not work correctly
when USE_DEFAULT_RT=No.

USE_PHYSICAL_NAMES=[Yes|No]

Added in Shorewall 4.4.27. Normally, when Shorewall creates a
Netfilter chain that relates to an interface, it uses the
interface's logical name as the base of the chain name. For example,
if the logical name for an interface is OAKLAND, then the input
chain for traffic arriving on that interface would be 'OAKLAND_in'.
If this option is set to Yes, then the physical name of the
interface will be used the base of the chain name.

USE_RT_NAMES=[Yes|No]

Added in Shorewall 4.5.15. When set to 'Yes', Shorewall will
use routing table (provider) names in the generated script rather
than table numbers. When set to 'No' (the default), routing table
numbers will be used.

Caution

If you set USE_RT_NAMES=Yes and KEEP_RT_TABLES=Yes, then you
must insure that all of your providers have entries in
/etc/iproute2/rt_tables as well as the following entries:

255 local

254 main

253 default

250 balance

0 unspec

Without these entries, the firewall will fail to
start.

VERBOSE_MESSAGES=[Yes|No]

Added in Shorewall 5.0.9. When Yes (the default), messages
produced by the ?INFO and ?WARNING directives include the filename
and linenumber of the directive. When set to No, that additional
information is omitted. The setting may be overridden on a directive
by directive basis by following ?INFO or ?WARNING with '!' (no
intervening white space).

VERBOSITY=[number]

Shorewall has traditionally been very noisy (produced lots of
output). You may set the default level of verbosity using the
VERBOSITY OPTION.

Values are:

0 - Silent. You may make it more verbose using the -v
option

1 - Major progress messages displayed

2 - All progress messages displayed (pre Shorewall-3.2.0
behavior)

If not specified, then 2 is assumed.

WARNOLDCAPVERSION=[Yes|No]

Added in Shorewall 4.5.12. When set to Yes (the default), the compiler issues a
warning when it finds a capabilities file that doesn't specify all
of the capabilities supported by the compiler. When
WARNOLDCAPVERSION is set to No, no
warning is issued.

WORKAROUNDS=[Yes|No]

Added in Shorewall 4.6.11. Over time, there have been a number
of changes in Shorewall that work around defects in other products
such as iptables and ipset. When WORKAROUNDS=Yes, these workarounds
are enabled; when WORKAROUNDS=No, they are disabled. If not
specified or if specified as empty, WORKAROUNDS=Yes is
assumed.

Warning

Do not set WORKAROUNDS=Yes if you need to be able to use
Shorewall-generated scripts (such as created by the
save command) built by Shorewall 4.4.7 or
older.

ZERO_MARKS=[Yes|No]

Added in Shorewall 5.0.12, this is a workaround for an issue
where packet marks are not zeroed by the kernel. It should be set to
No (the default) unless you find that incoming packets are being
mis-routed for no apparent reasons.

Caution

Do not set this option to Yes if you have IPSEC software
running on the firewall system.

ZONE_BITS=[number]

Added in Shorewall 4.4.26. When non-zero, enables automatic
packet marking by source zone and determines the number of bits in
the 32-bit packet mark to be used for the zone mark. Default value
is 0.